This invention relates in general to apparatus of the type in which certain interrelated operating parameters must be set before use and, more particularly, to an improved spectrophotometric apparatus permitting the selection of predetermined combinations of operating parameters.
In certain known types of apparatus, a number of interrelated parameters must be set before use. In some of these, the operator is allowed free choice of parameters, each within a given range, and in some he is limited to predetermined combinations of operating parameters. This invention is concerned with apparatus providing the latter mode of operation, which will hereinafter be called "integrated mode". A typical apparatus in which integrated mode facilities may be found is a spectrophotometer, wherein the major operating parameters are resolution, noise filter time constant and wavenumber scan time.
The justification for integrated mode operation is the ease with which personnel can be instructed to use the spectrophotometer, as they are not required to seek the fine compromise that must be arrived at in trading off resolution and signal-to-noise ratio against each other while maintaining good line shape of the recorded spectrum and reasonable wavenumber scan times. By carefully matching the parameters of each selectable combination, the manufacturer effectively builds into the integrated mode system the skill and judgement of the professional analyst with years of experience behind him and makes it available to the novice at the touch of a button.
It would largely defeat the object to the convenience of the user thus provided if the selection of the preset combinations was not made easy and self-evident such as by providing an array of push buttons of reasonable size. Unfortunately, such an array takes up a great deal of panel space, with the result that the range of selectable combinations must be limited. This is perhaps the reason why integrated mode operation has appeared so far only as an ancillary to the operation normally provided in which the user has a free choice of parameters.
In the present context, the phrase "integrated mode" shall apply to any apparatus falling within the scope of the present invention and not just to spectrophotometers. Furthermore, the phase "main mode" shall be understood to refer to a predetermined combination of matched parameters included in the design range of an integrated mode system. The term "auxiliary mode" shall refer to a predetermined combination of matched parameters resulting from a modification of a main mode. Parameters are said to be matched when they conform at least approximately to a suitable criterion of apparatus performance.